Prior to the Glory win, the Phoenix were conceding far too many goals and North believes that some strengthening in the defence will help lift results as the forwards are doing their bit at the other end of the pitch.
"To have a clean sheet was great, I was pretty happy with the defensive effort from the boys," said North. "We've leaked too many goals previously (22 in 13 matches) - it's ridiculous how many we've conceded.
"We've just copped silly goals, that's what's killed us. We've been scoring enough (16) but conceding soft goals just isn't good enough."
The Phoenix host the third-placed Mariners on Saturday evening and North, who was called up for the Australian national team during the week, knows what to expect when the Gosford club comes to town.
"Same as always - very hard-working and well coached. They've shown they can score goals, putting five past Perth in Sydney a couple of weeks back, and they're sitting near the top now," he added.
"Whenever I've played against the Central Coast you've always had to be switched on and making sure you're doing your job. On Saturday night it'll be case of winning the battle first and getting over the top of them.
"They've always had that hard-working mentality and that's something we've got to match. If we don't match it then we'll be in for a tough time."